In this tutorial, we will discuss how to install, configure, use and get the most out of OpenBuilds CONTROL. For machine building and controller wiring, please refer to the OpenBuilds documentation site.


OpenBuilds CONTROL is a free to use application that allows you to connect and control a grbl/grblHal based CNC router, laser, plasma or drag knife machine. The application is easy to use and targeted toward the beginner. It has a ton of functionality built-in, including wizards for surfacing your spoil board and calibrating your axis steps, as well as probing routines to help set up your jobs quickly and accurately.


OpenBuilds CONTROL can be installed on a PC, Mac or Linux machine. You can download it here: While not officially supported, OpenBuilds CONTROL can also be installed on a Raspberry Pi 4:

CONTROL sits in the system tray waiting to be launched. The user interface can be launched by right-clicking the icon and selecting “Open User Interface”.

How to open the CONTROL user interface.
How to open the CONTROL user interface.

Connecting your controller

Depending on your controller, you can connect CONTROL via USB or WIFI. If you are connecting to a controller that’s already configured, you can select the port your controller is connected to in the port selection dropdown list and skip to Setting up jobs.

When setting up a new controller, you’ll have have to install device drivers, connect via USB and then configure grbl / grblHal. For the new BlackBox X32, you’ll have to go through USB setup before you can connect via WIFI.

To connect to your controller via a usb cable, you’ll need to install the FTDI drivers. Those drivers can be found here:

After the device drivers are installed, you can select your controller port in the Connect dropdown list.

OpenBuilds CONTROL port selection dropdown list.
OpenBuilds CONTROL port selection dropdown list.

Configure grbl / grblHal

The easiest way to configure grbl or grblHal, on a new controller, is to use one of the machine profiles provided by CONTROL. Even if you dont have an OpenBuilds CNC machine, you can use a machine profile to get started, then customize it to match your machine specs. To load a machine profile, click on the grbl settings tab. Then select a machine profile that’s similar to your machine.

STOP! Only do this for a new controller! Do not follow these steps if you have a controller you’ve already configured using a different gcode sender application!

OpenBuilds CONTROL machine profiles.
OpenBuilds CONTROL tutorial using machine profiles.

If your cnc machine is not listed, you can select a similar machine. For belt driven machines, use the OpenBuilds Workbee 1515 profile (you can change the machine size later). For screw driven machines, use one of the OpenBuilds Lead profiles.

After you make your selection, click the Save to Firmware button.

Verifying machine setup

At this point I’m sure you are eager to cut your first project. However, there are several steps to complete first.

1 – Verify that your machine is moving in the correct direction. Use the jog buttons to move the machine around. Z+ should move the spindle up. For a moving gantry style machine, X+ should move the spindle to the right and Y+ should move the spindle away from you. For fixed gantry style machines, X+ should move the table to the left and Y+ should move the table closer to you.

If any of your axis are not moving in the correct direction, you can fix this by going into the grbl settings tab and switching the step direction (setting $3) for that specific axis.

grbl $3 step direction invert settings
grbl $3 step direction invert settings

2 – Verify your machine moves accurately by using the Calibration Wizards. Using a machine profile is a quick way to get your machine configured, you’ll want to dial in your steps/mm settings for each axis to ensure your machine will be as accurate as it can be. CONTROL has 3 calibration wizards that will assist you in figuring out and automatically settings the correct values for grbl’s steps/mm settings ($100, $111 and $112). The following video is a bit outdated, but should help you understand how to use the Calibration Wizards.

OpenBuilds CONTROL calibration wizards.

Its really best to calibrate your machine over a long distance. Luckily the calibration wizards now let you calibrate over a custom distance. Also, I prefer to use a precision ruler over a tape measure.

3 – Test your limit switches. Even though limit switches are not required, they are an inexpensive way to protect your machine against some over travel crashes and allows a simpler way to home your machine. I suggest using the OpenBuilds Xtension Limit Switch kit. The have onboard noise filtering to prevent false triggers and are really easy to install.

To use limit switches on your machine, make sure they are enabled in the grbl setting tab.

OpenBuilds CONTROL enable limit switches
OpenBuilds CONTROL tutorial: enable limit switches

Once enabled, OpenBuilds CONTROL offers a simple way to determine if your limit switches are working or not. Click on the troubleshooting tab and you’ll see a status list for all of your limit switches.

OpenBuilds CONTROL verifying limit switches.
OpenBuilds CONTROL tutorial: verifying limit switches.

Trigger each limit switch with your finger. If the status changes from green/OFF to red/Triggered, then you know your limit switches are working properly and can now set up homing and soft limits.

4 – Set up machine homing. Machine homing is the process that allows your machine to know where its at. Its an essential process if you want to be able to shutdown your machine at the end of the day and pickup where you left off the next day. Its also used to determine the soft limits of the machine. Home your machine anytime the controller is reset or after a machine crash. To enable homing, change setting $22 (Homing cycle enabled) to 1 (enabled). Click the Save to Firmware button.

Next, you’ll want to verify that the homing directions are configured correctly. Click on the Home All button in CONTROL. The machine should first move the spindle up to Z limit switch. If the machine moves the spindle down to find the switch, click ABORT and change grbl setting $23 to invert the Z axis homing direction.

grbl's homing direction settings
grbl’s homing direction settings

After the homing process finds the Z limit switch it will move the X and Y axis towards the X and Y limit switches. If homing is searching away from where your limit switches are installed, click ABORT, then change the GRBL setting to $23.

As mentioned previously, limit switches are not required. If you dont have limit switches installed you can fake homing. There’s information on how to do this located on the OpenBuilds Forums.

Setting and Running up jobs

In the coming weeks, I’ll be adding more information on setting up jobs. For now, the OpenBuilds Hello World video posted below is a good place to start.

Customizing Control with macros

Macros, or more specifically Javascript Macros, are a powerful way to customize the OpenBuilds CONTROL UI or optimize your workflow. There are several posts on my blog about learning javascript macros, adding keyboard shortcuts or even tweaking the UI to suit your needs.

If writing javascript code is not your thing, I have several macros available in my store. These include:

Grid Line Wizard which will automatically generate gcode to cut grid lines into your spoilboard

Machine Coordinates DRO which will add a machine coordiates display to CONTROL.

Widescreen UI which makes CONTROL utilize space more efficiently on widescreen monitors.

Widescreen UI for OpenBuilds CONTROL

I hope you find the information in this OpenBuilds tutorial helpful. If you have any questions, feel free to contact me.

OpenBuilds Products I Use (affiliate):

OpenBuilds CONTROL​
Workbee 1510​ (similar to Lead 1010 or Lead 1515)
BlackBox Motion Controller​
BlackBox X32 Motion Controller
Interface CNC Touch Controller​
XYZ Touch Probe Plus


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